Although the outcome of extremely low birth weight (ELBW) infants weighing 401-1000 gms has steadily improved over the past 15 years, these infants continue to face a high mortality rate (approximately 25%) and a high incidence of chronic lung disease among survivors (approximately 30%). Evidence from four relatively small clinical trials suggests that vitamin A, or retinol, deficiency in this population may contribute to the severity and incidence of chronic lung disease. The present study is designed to test the hypothesis that Vitamin A supplementation at 2-3 times the recommended routine dose in the ELBW infant will reduce the risk of chronic lung disease and/or death. Most ELBW infants receive intravenous nutrition as their primary energy source for the first 2-3 weeks of life, with about 900 IU vitamin A. When receiving full formula feedings, they generally receive about 900 IU vitamin A per day. However, absorption of either IV vitamin A (which sticks to the IV tubing) or oral vitamin A (which is <50%) is inadequate to meet recommended intakes. This will be a multicenter, randomized, placebo controlled, double-masked prospective trial supported by the National Institute of Child Health and Human Development. Eligible infants will be enrolled between 24 and 96 hours after birth and stratified by birthweight categories (401-750 gms and 751-1000 gms). Within each group, infants will be randomly assigned to treatment (Vitamin A supplementation at greater than routine doses) versus non-treatment or placebo (no extra supplementation provided). Based on an anticipated reduction in death or chronic lung disease of 20%, a total of 780 infants (390 in each group) is required. The study will be performed in the twelve participating newborn intensive care centers of the NIH sponsored Neonatal Network.